kc5tja: Have you looked into etherbone, or any of the other CERN Wishbone projects? I think they have some infrastructure for external wishbone buses. Some of it is even in the upstream Linux kernel since Alessandro Rubini is quite involved with those things

kc5tja: If I remember correctly from your web pages, you have multiple "slaves" on a physical bus acting in concert, no? If not, how on earth are you able to handle a "graphics heavy" machine if your CPU is filling up the FPGA?